Recent content by welshtill

  1. W

    Superfluid mass density

    By Landau's theory the normal mass density(total density minus the superfluid mass density) is the total mass carried by excitations. For the BCS state and weakly interacting Bose gas the normal density is zero at zero temperature because there are no excitations. However in the presence of...
  2. W

    Many-body hilbert space

    I now understand this relation, 1 is a unit operator in sub-hilbert space Hf or Hb.
  3. W

    Many-body hilbert space

    I am reading J.W.Negele and H.Orland's book "Quantum Many-Particle Systems". I don't know how one can derive equation (1.40) on page 6. The question is For quantum many-body physics, suppose there are N particles. The hilbert space is H_{N}=H\otimesH\otimes...H. Its basis can be...
  4. W

    Two dimensional green function

    what confused me is this equation: i cann't find anywhere the derivation of this relation.
  5. W

    Two dimensional green function

    thanks for shawl, i am sorry that i forgot to post the book's name.the attached file is taken from "methods of theoretical physics, part 2" by Philip M. Morse and Herman Feshbach, on page 1362.
  6. W

    Two dimensional green function

    In studying the scattering problem, one should know green function in free space. while in two dimension, green function is the hankel function, seen in the attached file. bu i got confused in the second equation in the attached file. could anyone give me some details about this relationship? it...
  7. W

    Self consistent spin wave theory

    This is more like a Bogoliubov's method.
  8. W

    Fluctuation Terms in Landau Theory

    GL's equation was first obtained from phenomenological consideration plus some symmetry constraints. Microscopic alculation can be performed by path-integral method in a more clearer way. Details are given in A.Altland and B.Simons book:"condensed matter field theory" on page286.
  9. W

    Matsubara frequency convergency factor

    thanks. i am not at Cambridge. for your question, I don't know the answer. some one asked me this question long before. what i know is matsubara summation is nothing but a summation caused by Fourier transformation, like momentum.
  10. W

    Matsubara frequency convergency factor

    hi, everyone,this is the first time i put a thread here. thanks in advance i am now learning functional integral techniques in condensed matter physics.when dealing with Matsubara frequency summations,one will meet with the convergency factor(for example...
Back
Top